If a rouge can catch an opponent when he is unable to defend himself effectively from her attack, she can strike a vital spot for extra damage. This can be done either by attacking when the target is unaware of the rouge or if the they are attacking from the target from the rear. The rouge does an additional 1 points of damage for each level of sneak attack. The rouge can only sneak attack with daggers or short swords.

Weapon Proficiency

Class

Can wield a Dagger without penalty

Armor Proficiency

Class

Can use Light Armor without penalty

Combat Expertise

From Flaw

When you use the attack action or the full attack action in melee, you can take a penalty of as much as -5 on your attack roll and add the same number (+5 or less) as a dodge bonus to your Armor Class. This number may not exceed your base attack bonus. The changes to attack rolls and Armor Class last until your next action.